E-bike battery layout help.

[GeorgeR]

I bought a chamrider polly 7 21700 52v 14s5p empty case with nickel strips, I had found a layout for this care beforehand (I thought). When the case arrived the nickel strips were not the same as the layout I had found for this case, nickel strips are different. I'm not new to lithium batteries as I have been living off grid for years. But this is another kind of animal.. I have a picture of the nickel strips in place, any assistance would be appreciated. I believe i go neg, pos, neg, longways at first, but I'm just not certain near the end. I realize this puzzle blows up if you get it wrong View attachment S82cc45e71fe945ae95e35d0da4a8e43fD.webp

 

[TPEHAK]

That looks correct for me. When you will weld it cover all the batteries terminals you are not welding with masking tape and keep exposed only the terminal you are welding on. Before welding take a soldering line and put it on top of all the batteries terminals you are planning to weld the tab on before welding the tab to check there in nothing wrong (If there is something wrong it will just melt the soldering line). Work with eye protection and gloves.

 

[GeorgeR]

You sir, are freaking awesome!

 

[GeorgeR]

Good advice, especially the solder for heat discovery. Thank You!

 

[Nix Liou]

Good advice, especially the solder for heat discovery. Thank You!

If you have a multimeter you can also just check the voltage/continuity between the cathodes and anodes you are about to spot weld. That way you don't need to melt solder onto anything.

Technically, you can put all the strips onto one side of the battery without insulating, and then put masking tape on the other side. Better safe than sorry though

 

[GeorgeR]

I do have a multimeter. Would be easier than soldering.

 

[GeorgeR]

Would be bad if a strip touched the wrong place...

 

[TPEHAK]

Also pay attention you have a quite narrow bottleneck. That series connection looks like one narrow layer of nickel. But if you assemble an existing kit with BMS supplied with this kit it is probably taken to consideration. If you use your own BMS you might want to check that section size and see if it is suitable for the amperage you are planning to squeeze out of this battery pack.

 

[GeorgeR]

Your right. I think I'll layer a bit of nickel strip on that spot with the spot welder. zero specs on the amperage, I have a 30 amp bms for it. it's going on a paltry 500W bafang fat tire rear wheel.. I doubt that thing will draw near enough to cause a problem. Better safe than sorry though!

 

[docw009]

As we all know, the battery current will neck down to the small spot between the two groups on the longest strip. It's probably nickel plated steel. Won't melt, but might cost a volt at full throttle, Just for good practices, both it and the shorter piece on the other side ought to be bridged.

For this, I prefer copper wire instead of extra layers for such limited use cases, I would solder a length of wire alongside the strip edge before spot welding them.